We can see that clustering with the method single, gives us the worst
result, the cluster splits are very small and not vertically balanced.
The average method gives us better results, we can already see clusters
more higher up in the tree, but on the left we can see a cluster, whcih
is not taking into regard in the higher clusters. In the complete
clustering we see reasonable balanced clusters, and we see that the
first 2 clusters at the top include all the songs.
